Correct Answer: B

Rationale: The independent variable in this scenario is 'Stocks.' An independent variable is the one that is manipulated or controlled by the experimenter. In this case, stocks are the factor that is changing and influencing the other variables - production, sales, and investments. Production, sales, and investments are dependent on the changes in stocks; hence, they are the dependent variables. While production, sales, and investments may increase as a result of changes in stocks, the stocks themselves are the driving force behind these changes, making them the independent variable.

Correct Answer: A

Rationale: The correct answer is A: 'Itself.' When any number is raised to the power of 1, it remains unchanged and is equal to itself. This is a fundamental property of exponents. Choice B, 'One,' is incorrect because raising a number to the power of 1 does not result in the answer being 1. Choice C, 'Zero,' is incorrect as any non-zero number raised to the power of 1 is itself, not zero. Choice D, 'The number multiplied by 2,' is incorrect because raising a number to the power of 1 does not involve multiplying it by 2.

Correct Answer: D

Rationale: To find the area of a circle, we use the formula A = πr², where r is the radius of the circle. In this case, the diameter is 9 inches, so the radius is half of the diameter, which is 4.5 inches. Substituting the radius into the formula, we get A = π(4.5)² = 20.25 πin². Therefore, the correct answer is 20.25 πin². Choices A, B, and C are incorrect because they do not correctly calculate the area using the radius of the circle.

Correct Answer: A

Rationale: The correct expression for the sum of three times a number and eight times a different number is given by 3x + 8y. This represents adding three times the variable x (3x) to eight times the variable y (8y). Choice B (8x + 3x) is incorrect as it represents adding eight times x to three times x, which is redundant. Choice C (3x - 8y) is incorrect because it represents subtracting eight times y from three times x, not their sum. Choice D (8x - 3y) is also incorrect as it represents subtracting three times y from eight times x, not their sum.

Correct Answer: C

Rationale: To convert kilograms to pounds, multiply the weight in kilograms by the conversion factor 2.2 (1 kg = 2.2 lbs). Therefore, 45 kg * 2.2 lbs/kg = 99 lbs. Choice A is incorrect because it is a miscalculation. Choice B is incorrect as it does not reflect the correct conversion. Choice D is incorrect as it is also a miscalculation of the conversion.